The Mass Spectrometry (MS) Core of the Washington University Diabetes Research Center (DRC) increases DRC efficiency and cost effectiveness by performing MS analyses for affiliated investigators. The MS Core provides state-of-the-art MS services to determine structures and to quantitate amounts of diabetes-related biomolecules. The MS Core provides centralized, standardized analytical procedures that permit study of molecular mechanisms of the pathogenesis of diabetes mellitus, its risk factors, and its complications, including the metabolic syndrome, obesity, atherosclerosis, and increased susceptibility to infections. Speciflc objectives of the DRC MS Core are: 1. To provide training to students and fellows in principles of MS and use of MS systems, e.g., gas chromatography (GC)/MS, isotope ratio (IR)/MS, electrospray ionization (ESI)/tandem MS, and matrix assisted laser desorption ionization (MALDI)/time of fiight/(TOF)/MS in analyses of diabetes-related biomolecules. To develop new MS methods for structural identification and quantitation of molecules involved in diabetes, its risk factors and complications, and related physiologic and pathophysiologic events. To perform service MS analyses, e.g. quantitation of target analytes and obtaining spectra for structural i identification, for DRTC Investigators. To assist DRC-affiliated investigators in developing MS assays. To provide consultation in interpreting MS data. To develop and disseminate new approaches in biomedical MS that are applicable to diabetes research. To provide and maintain functional MS systems for use in diabetes research. To perform collaborative diabetes research studies involving MS Core staff requiring specialized expertise, e.g.. Stable Isotope Labeling in Cell Culture (SILAC), Stable Isotpe Labeling Tandem Mass Spectrometry (SILT), characterization of post-translational modifications or protein-protein interactions, or studies of complex lipids that require de novo structure determination. 9. To reduce diabetes research costs by providing centralized MS services at a fraction of the cost of commercial MS services or of maintaining instruments in the laboratories of individual investigators.